diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,8 @@
+## Juicy Pixels Extra 0.6.0
+
+* Added new functions `trim` and `square`. [See PR
+  34](https://github.com/mrkkrp/JuicyPixels-extra/pull/34).
+
 ## Juicy Pixels Extra 0.5.2
 
 * Replacing CPP preprocessing rules with expicit SPECIALIZE pragmas. [See PR
diff --git a/Codec/Picture/Extra.hs b/Codec/Picture/Extra.hs
--- a/Codec/Picture/Extra.hs
+++ b/Codec/Picture/Extra.hs
@@ -19,6 +19,7 @@
 
     -- * Cropping
     crop,
+    trim,
 
     -- * Rotation
     flipHorizontally,
@@ -30,13 +31,15 @@
     -- * Other
     beside,
     below,
+    square,
   )
 where
 
 import Codec.Picture
 import qualified Codec.Picture.Types as M
 import Control.Monad.ST
-import Data.List (foldl1')
+import Data.List (find, foldl1')
+import Data.Maybe (fromMaybe)
 
 -- | Scale an image using bi-linear interpolation.
 scaleBilinear ::
@@ -54,32 +57,32 @@
   Image a
 scaleBilinear width height img@Image {..}
   | width <= 0 || height <= 0 =
-    generateImage (error "scaleBilinear: absurd") (max 0 width) (max 0 height)
+      generateImage (error "scaleBilinear: absurd") (max 0 width) (max 0 height)
   | otherwise = runST $ do
-    mimg <- M.newMutableImage width height
-    let sx, sy :: Float
-        sx = fromIntegral imageWidth / fromIntegral width
-        sy = fromIntegral imageHeight / fromIntegral height
-        go x' y'
-          | x' >= width = go 0 (y' + 1)
-          | y' >= height = M.unsafeFreezeImage mimg
-          | otherwise = do
-            let xf = fromIntegral x' * sx
-                yf = fromIntegral y' * sy
-                x, y :: Int
-                x = floor xf
-                y = floor yf
-                δx = xf - fromIntegral x
-                δy = yf - fromIntegral y
-                pixelAt' i j =
-                  pixelAt img (min (pred imageWidth) i) (min (pred imageHeight) j)
-            writePixel mimg x' y' $
-              mulp (pixelAt' x y) ((1 - δx) * (1 - δy))
-                `addp` mulp (pixelAt' (x + 1) y) (δx * (1 - δy))
-                `addp` mulp (pixelAt' x (y + 1)) ((1 - δx) * δy)
-                `addp` mulp (pixelAt' (x + 1) (y + 1)) (δx * δy)
-            go (x' + 1) y'
-    go 0 0
+      mimg <- M.newMutableImage width height
+      let sx, sy :: Float
+          sx = fromIntegral imageWidth / fromIntegral width
+          sy = fromIntegral imageHeight / fromIntegral height
+          go x' y'
+            | x' >= width = go 0 (y' + 1)
+            | y' >= height = M.unsafeFreezeImage mimg
+            | otherwise = do
+                let xf = fromIntegral x' * sx
+                    yf = fromIntegral y' * sy
+                    x, y :: Int
+                    x = floor xf
+                    y = floor yf
+                    δx = xf - fromIntegral x
+                    δy = yf - fromIntegral y
+                    pixelAt' i j =
+                      pixelAt img (min (pred imageWidth) i) (min (pred imageHeight) j)
+                writePixel mimg x' y' $
+                  mulp (pixelAt' x y) ((1 - δx) * (1 - δy))
+                    `addp` mulp (pixelAt' (x + 1) y) (δx * (1 - δy))
+                    `addp` mulp (pixelAt' x (y + 1)) ((1 - δx) * δy)
+                    `addp` mulp (pixelAt' (x + 1) (y + 1)) (δx * δy)
+                go (x' + 1) y'
+      go 0 0
 {-# SPECIALIZE scaleBilinear :: Int -> Int -> Image M.PixelRGBA16 -> Image M.PixelRGBA16 #-}
 {-# SPECIALIZE scaleBilinear :: Int -> Int -> Image M.PixelRGBA8 -> Image M.PixelRGBA8 #-}
 {-# SPECIALIZE scaleBilinear :: Int -> Int -> Image M.PixelCMYK16 -> Image M.PixelCMYK16 #-}
@@ -140,6 +143,25 @@
     h = min (imageHeight - y) h'
 {-# INLINEABLE crop #-}
 
+-- | Trim the completely transparent edges of an image.
+--
+-- @since 0.6.0
+trim :: (Pixel a, Eq (PixelBaseComponent a)) => Image a -> Image a
+trim img@Image {..} = crop left top width height img
+  where
+    isInvisible p = pixelOpacity p == 0
+    isInvisibleRow y = all isInvisible $ flip (pixelAt img) y <$> [0 .. imageWidth - 1]
+    isInvisibleCol x = all isInvisible $ pixelAt img x <$> [0 .. imageHeight - 1]
+
+    top = fromMaybe 0 (find (not . isInvisibleRow) [0 .. imageHeight - 1])
+    bottom = fromMaybe 0 (find (not . isInvisibleRow) [imageHeight - 1, imageHeight - 2 .. 0]) + 1
+    height = bottom - top
+
+    left = fromMaybe 0 (find (not . isInvisibleCol) [0 .. imageWidth - 1])
+    right = fromMaybe 0 (find (not . isInvisibleCol) [imageWidth - 1, imageWidth - 2 .. 1]) + 1
+    width = right - left
+{-# INLINEABLE trim #-}
+
 -- | Flip an image horizontally.
 flipHorizontally :: Pixel a => Image a -> Image a
 flipHorizontally img@Image {..} =
@@ -214,3 +236,24 @@
           | otherwise = pixelAt img2 x (y - h1)
         w = min w1 w2
 {-# INLINEABLE below #-}
+
+-- | Make an image a perfect square by adding filler around it.
+--
+-- @since 0.6.0
+square :: Pixel a => a -> Image a -> Image a
+square filler img@Image {..} =
+  if imageWidth == imageHeight
+    then img
+    else generateImage gen size size
+  where
+    size = max imageWidth imageHeight
+    extraWidth = size - imageWidth
+    extraHeight = size - imageHeight
+    offsetX = extraWidth `div` 2
+    offsetY = extraHeight `div` 2
+    gen i _ | i < offsetX = filler
+    gen i _ | i >= imageWidth + offsetX = filler
+    gen _ j | j < offsetY = filler
+    gen _ j | j >= imageHeight + offsetY = filler
+    gen i j = pixelAt img (i - offsetX) (j - offsetY)
+{-# INLINEABLE square #-}
diff --git a/JuicyPixels-extra.cabal b/JuicyPixels-extra.cabal
--- a/JuicyPixels-extra.cabal
+++ b/JuicyPixels-extra.cabal
@@ -1,11 +1,11 @@
-cabal-version:   1.18
+cabal-version:   2.4
 name:            JuicyPixels-extra
-version:         0.5.2
-license:         BSD3
+version:         0.6.0
+license:         BSD-3-Clause
 license-file:    LICENSE.md
 maintainer:      Mark Karpov <markkarpov92@gmail.com>
 author:          Mark Karpov <markkarpov92@gmail.com>
-tested-with:     ghc ==8.8.4 ghc ==8.10.5 ghc ==9.0.1
+tested-with:     ghc ==9.0.2 ghc ==9.2.4 ghc ==9.4.1
 homepage:        https://github.com/mrkkrp/JuicyPixels-extra
 bug-reports:     https://github.com/mrkkrp/JuicyPixels-extra/issues
 synopsis:        Efficiently scale, crop, flip images with JuicyPixels
@@ -30,7 +30,7 @@
     exposed-modules:  Codec.Picture.Extra
     default-language: Haskell2010
     build-depends:
-        base >=4.13 && <5,
+        base >=4.15 && <5,
         JuicyPixels >=3.2.6.4 && <3.4
 
     if flag(dev)
@@ -45,14 +45,14 @@
             -Wnoncanonical-monad-instances
 
 test-suite tests
-    type:             exitcode-stdio-1.0
-    main-is:          Spec.hs
-    build-tools:      hspec-discover >=2.0 && <3.0
-    hs-source-dirs:   tests
-    other-modules:    Codec.Picture.ExtraSpec
-    default-language: Haskell2010
+    type:               exitcode-stdio-1.0
+    main-is:            Spec.hs
+    build-tool-depends: hspec-discover:hspec-discover >=2.0 && <3.0
+    hs-source-dirs:     tests
+    other-modules:      Codec.Picture.ExtraSpec
+    default-language:   Haskell2010
     build-depends:
-        base >=4.13 && <5,
+        base >=4.15 && <5,
         JuicyPixels >=3.2.6.4 && <3.4,
         JuicyPixels-extra,
         hspec >=2.0
@@ -69,10 +69,10 @@
     hs-source-dirs:   bench
     default-language: Haskell2010
     build-depends:
-        base >=4.13 && <5,
+        base >=4.15 && <5,
         JuicyPixels >=3.2.6.4 && <3.4,
         JuicyPixels-extra,
-        criterion >=0.6.2.1 && <1.6
+        criterion >=0.6.2.1 && <1.7
 
     if flag(dev)
         ghc-options: -O2 -Wall -Werror
diff --git a/data-examples/fully-transparent.png b/data-examples/fully-transparent.png
new file mode 100644
Binary files /dev/null and b/data-examples/fully-transparent.png differ
diff --git a/data-examples/macaque-transparent-cropped.png b/data-examples/macaque-transparent-cropped.png
new file mode 100644
Binary files /dev/null and b/data-examples/macaque-transparent-cropped.png differ
diff --git a/data-examples/macaque-transparent.png b/data-examples/macaque-transparent.png
new file mode 100644
Binary files /dev/null and b/data-examples/macaque-transparent.png differ
diff --git a/tests/Codec/Picture/ExtraSpec.hs b/tests/Codec/Picture/ExtraSpec.hs
--- a/tests/Codec/Picture/ExtraSpec.hs
+++ b/tests/Codec/Picture/ExtraSpec.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE FlexibleContexts #-}
+
 module Codec.Picture.ExtraSpec
   ( main,
     spec,
@@ -8,6 +10,7 @@
 import Codec.Picture.Extra
 import Control.Monad
 import Data.Function (on)
+import Foreign (Storable)
 import Test.Hspec
 
 main :: IO ()
@@ -17,6 +20,7 @@
 spec = do
   describe "scaleBilinear" scaleBilinearSpec
   describe "crop" cropSpec
+  describe "trim" trimSpec
   describe "flipHorizontally" flipHorizontallySpec
   describe "flipVertically" flipVerticallySpec
   describe "rotateLeft90Spec" rotateLeft90Spec
@@ -24,6 +28,7 @@
   describe "rotate180" rotate180Spec
   describe "beside" besideSpec
   describe "below" belowSpec
+  describe "square" squareSpec
 
 scaleBilinearSpec :: Spec
 scaleBilinearSpec = do
@@ -79,6 +84,32 @@
         "data-examples/macaque-below.png"
         "data-examples/macaque.png"
 
+trimSpec :: Spec
+trimSpec = do
+  context "when we pass an image without transparency" $
+    it "does nothing" $
+      checkWithFiles
+        trim
+        "data-examples/macaque.png"
+        "data-examples/macaque.png"
+  context "when passing an image with transparency" $ do
+    it "does nothing if there are no fully transparent edges" $
+      checkWithFilesAlpha
+        trim
+        "data-examples/macaque-transparent-cropped.png"
+        "data-examples/macaque-transparent-cropped.png"
+    it "removed the transparent edges" $
+      checkWithFilesAlpha
+        trim
+        "data-examples/macaque-transparent.png"
+        "data-examples/macaque-transparent-cropped.png"
+  context "when passing a fully transparent image" $
+    it "returns an empty image" $ do
+      (Right (ImageRGBA8 original)) <- readImage "data-examples/fully-transparent.png"
+      let trimmed = trim original
+      imageWidth trimmed `shouldBe` 1
+      imageHeight trimmed `shouldBe` 1
+
 flipHorizontallySpec :: Spec
 flipHorizontallySpec =
   context "when we flip horizontally" $
@@ -142,6 +173,31 @@
         "data-examples/macaque.png"
         "data-examples/macaque-below.png"
 
+squareSpec :: Spec
+squareSpec = do
+  context "when we pass an already square image" $ do
+    it "does nothing" $
+      checkWithFiles
+        (square $ PixelRGB8 0 0 0)
+        "data-examples/macaque.png"
+        "data-examples/macaque.png"
+    it "does nothing (alpha)" $
+      checkWithFilesAlpha
+        (square $ PixelRGBA8 0 0 0 0)
+        "data-examples/macaque-transparent.png"
+        "data-examples/macaque-transparent.png"
+  context "when we pass a non-square image" $ do
+    it "adds the required filler to wider than heigh image" $ do
+      (Right (ImageRGB8 original)) <- readImage "data-examples/macaque-beside.png"
+      let squared = square (PixelRGB8 0 0 0) original
+      imageWidth squared `shouldBe` 1024
+      imageHeight squared `shouldBe` 1024
+    it "adds the required filler to higher than wide image" $ do
+      (Right (ImageRGB8 original)) <- readImage "data-examples/macaque-below.png"
+      let squared = square (PixelRGB8 0 0 0) original
+      imageWidth squared `shouldBe` 1024
+      imageHeight squared `shouldBe` 1024
+
 -- | Run a transforming on the image loaded from a file and compare the
 -- resulting image with the contents of another file.
 checkWithFiles ::
@@ -157,6 +213,20 @@
   (Right (ImageRGB8 result)) <- readImage fpath
   f original `blindlySatisfy` sameImage result
 
+-- | `checkWithFiles` for images with an alpha channel.
+checkWithFilesAlpha ::
+  -- | Transformation to test
+  (Image PixelRGBA8 -> Image PixelRGBA8) ->
+  -- | Where to get the original image
+  FilePath ->
+  -- | Where to get the image to compare with
+  FilePath ->
+  Expectation
+checkWithFilesAlpha f opath fpath = do
+  (Right (ImageRGBA8 original)) <- readImage opath
+  (Right (ImageRGBA8 result)) <- readImage fpath
+  f original `blindlySatisfy` sameImage result
+
 -- | The same as 'shouldSatisfy', but doesn't care if its argument is an
 -- instance of 'Show' or not.
 blindlySatisfy :: a -> (a -> Bool) -> Expectation
@@ -164,7 +234,7 @@
   unless (p v) (expectationFailure "predicate failed")
 
 -- | The equality test for images.
-sameImage :: Image PixelRGB8 -> Image PixelRGB8 -> Bool
+sameImage :: (Eq a, Eq (PixelBaseComponent a), Storable (PixelBaseComponent a)) => Image a -> Image a -> Bool
 sameImage a b =
   ((==) `on` imageWidth) a b
     && ((==) `on` imageHeight) a b